DE3149285C2 - Method for connecting the tubes of a heat exchanger matrix to the heat exchanger base of a collecting tank - Google Patents

Abstract

In an essential basic embodiment of the present invention, the respective tubular end should be hammered, forged or the like. deformed over a mandrel and coated with a soldering material after calibration of the outer contour, whereupon the so widened pipe end is inserted together with the mandrel into the associated hole in the heat exchanger base and when the mandrel is subsequently pulled through it is pressed against the adjacent walls of the hole and its wheels, after which a metallurgical connection between the pipe end and the relevant heat exchanger bottom section is established by local heating. In another essential embodiment of the invention, the associated hole in the heat exchanger base including the circumferential wall of the pipe in question should be designed to taper slightly conically in the direction of the inner wall of the heat exchanger base at the same angles of inclination, around the circumferential joint under both radial and axial surface pressure between the associated hole wall and to close the tubular end when the conical pipe end is pulled into the corresponding conical hole by means of the mandrel and its collar. In the context of all of these remarks and procedures, the heat exchanger tubes or profiles in question are to be used in a comparatively simple manner while ensuring optimum temperature resistance and sealing properties in the heat exchanger bottom parts .....

Description

The invention relates to a method according to the preamble of claim 1.

The invention also relates to a device for carrying out the method (claim 14).
"In a heat exchanger known, for example, from DE-OS 29 07 810, a first compressed air duct is provided, via which the high-pressure air of a gas turbine engine, for example conveyed by a compressor, can be fed to the relevant heat exchanger matrix, in which the high-pressure air is then applied as a result of hot gas This matrix is heated and finally flows out of the heat exchanger matrix into a second pipe guide, which is connected to a suitable consumer, in this case to the combustion chamber of this gas turbine engine. For example, in this known heat exchanger, the two separate pipe guides can be integrated into a common manifold , of which the relevant heat exchanger matrix is U-shaped on both sides

3 4

cantilever runs in particular a perfect seal between

In such a known heat exchanger, the pipe ends and the relevant! Bottom opening take into account that approx. 12,000 line connections were used. A fundamental principle essential to the invention or more "almost in one shot" with the relevant - thank you is that the pipe ends in question are already the heat exchanger base is to be soldered. These s before insertion into the relevant floor openings In the production of such heat, soldering is entirely covered with a layer of solder. Another a previously unresolved risk factor for this step, which is essential to the invention, is that this solder passes through represents that relatively large soldering gap or layer at the same time when making the connection in - Joints must be assumed, which are between the paths of the drawing or deformation process as well the respective pipe ends and the relevant Loch- io is pressed. In other words, adept must be located, assuming that the pulling through and / or pulling out the It is gen that a sufficiently large soldering gap along a Doras a form-fitting material compression flawless transport of the molten liquid supplied to the surfaces in question, namely with one another Must ensure solder. That means it consists in the end of the problem on the end of the matrix tube in question the risk that the molten solder 15 brought solder mass. It is therefore ensured that relocated to locally different zones, so that before the heating for the production of metallurbeim final cooling process no guarantee gisch perfect joint connection the respective joint there is that the relevant relatively large between the pipe end and the opening wall Soldering joints are continuously and perfectly pressed or eliminated over their entire circumference, which means that they are locally filled are. 20 before vertical shifts or changes are practical

In addition, practice has shown that these are relatively ruled out. The subject matter of the invention includes ßig large soldering joints for the provision of relatively large so the risk that this is within the scope of conventional Large soldering volumes increase the strength of such pipe-to-bottom connections in molten form can adversely affect bindings. In addition, solder can shift, so that during the final If a comparatively large soldering thickness is used in the cooling process, it will in any case be uniformly applied Joints with regard to the corrosion-related or homogeneous solder filling with absolute security disadvantageous. is guaranteed.

The invention is therefore based on the object of the invention based on I Ierstellungsverim Furthermore, within the scope of the problem outlined at the outset, only comparatively small amounts of solder are guided Eliminate disadvantages and produce a solution with a volume of 30 and correspondingly thin solder layers, with the relevant heat exchanger tubes required, which in turn is beneficial to the or -röhi chen or -profile on comparatively simple strength properties of the connection as well as on oak Color in the way while ensuring a comparatively low solder material requirement Temperature resistance and sealing capacity acts.

35 According to the invention, a comparatively

are cash. easy to create, perfectly dense, solid and

The task set is with the characteristics of such as corrosion-resistant pipe-soil connection for

Characteristic part of claim 1 of the invention created a heat exchanger,

solved according to. A device also known from GB-PS 1 98 851

In one of the types mentioned at the beginning (top bedding for fastening heat exchanger matrix pipes handle of claim 1) underlying be on the heat exchanger bottom can already from the point of view of known solution from DE-PS 4 83 878 is indeed also the type specified at the beginning (Rohrverpressungsvorschon a mandrel provided as a deformation tool, gang) does not lead to the invention. With this well-known at one end with an oak-shaped, the through-the-throat solution should, among other things. the individual "heat exchanger meters of the dome's widening provided 45 tubes initially in associated openings in a bottom is intended to be inserted into the tube plate in question when it is inserted and then along its outer opening to widen the pipe end in question and its end region to be widened radially in such a way that it to be pressed with at the side opposite the container wall. so only within the scope of this specified end range A major difference to this known Lö- contact the opening walls of the base plate The solution consists, in general terms, should be. The base plate should be designed in the manner of a trough according to the invention in the fact that the mandrel in question must be detached to later be immersed in a solder bath Bund from the beginning part of the heat exchange solder can be filled, which is from this That is, the pipe end to be used in the shear bottom is then distributed in the tub along the radial gap A path that should be directed exclusively from the outside to the inside, between the outer edges of the heat dew The pulling movement of the dome that takes place can thus damage the shear tubes and the relevant opening-side bob Pressing can be achieved without the turning parts having been kept free. The well-known case Lateral pulling or moving directions of a dome thus does not include the pre-soldering provision according to the invention to have to, as is the case with the above-mentioned coating and the subsequent pressing over the macaques Solution is required. trix tube ends in the bottom openings; rather it is

Another essential advantage of the case known when inventing a so-called "prime example"

the subject matter of interest from the outset for what, in view of the

trixrohrende, the cathedral and the federal government expressly comment on the subject matter of the invention.

in that the threading of the matrix tube end should be avoided straight; d. h, the known case

it is much easier to reach into the associated floor opening, among other things. comparatively large volumes of solder with the

especially since the mandrel diameter is always smaller than the 65 resulting consequences of weakness in strength

Bottom opening diameter is. chung and the risk of corrosion; also includes the

Furthermore, the known solution according to the DE-known case deals with the risk of non-uniform soldering

PS 4 83 878 no soldering provisions for the purpose of division with the resulting sealing risk

With regard to further advantageous refinements of the invention, reference is made to patent claims 2 to 14 referenced.

The invention is explained, for example, with the aid of the drawing; it shows

F i g. 1 one along the profile tube longitudinal center plane running partial section of a matrix pipe-floor connection in a first embodiment,

F i g. 2 shows a partial section of a matrix pipe-floor connection running along the longitudinal center plane of the profile in a second embodiment,

F i g. 3 one running along the profile center plane Partial section of a matrix tube-floor connection in a third embodiment and

F i g. 4 shows a section along the line IV-IV of FIG. 3.

F i g. 1 explains the method for producing the connection of a pipe end 1 of the pipe 2 belonging to a cross-countercurrent matrix of a heat exchanger with the corresponding pre-punched heat exchanger base 3, the pipe end 1 being initially deformed by hammering, forging or the like using a tool mandrel 4 and is coated with a soldering material, if necessary after calibration of the outer contour. The pipe end 1 is then inserted together with the tool mandrel 4 into the associated opening (hole wall 5) in the heat exchanger base 3 and, when the tool mandrel 4 is then pulled through, it is pressed against the adjacent hole wall 5 of the opening and its edges by means of its collar 6 in the direction of arrow F, after which it is pressed through local heating a metallurgical connection between the pipe end 1 and the relevant heat exchanger bottom part is established. Here, the outer contour of the pipe end 1 can be calibrated beforehand as precisely as is necessary to carry out the molding

Said heat exchanger base 3 belongs to the collecting tank of a heat exchanger, such Collection container can, for. B. for the respective compressed air supply or discharge in or from the relevant heat exchanger matrix be provided.

In the interests of efficient production, it should preferably be assumed that the metallurgical Connection of all pipe ends with the relevant heat exchanger base by heating in one Oven or the like takes place at the same time, ie "in one shot".

As further from FIG. 1 shows the tool mandrel 4 at its end adjacent to the outer wall of the heat exchanger base 3 denotes the mandrel wall or the collar 6 protruding in a rotationally symmetrical manner over the mandrel diameter for the previously described Pressing the pipe end 1 over the tool mandrel 4 is at the same time a rotationally symmetrical one that corresponds to the collar 6 Tube widening 7 is formed, which acts as a hole stop of the tube end 1 along with the profile of the tube 2 the outer wall of the heat exchanger base 3 is used

In addition, the outer contour of the pipe end 1 can simultaneously be deformed via the tool mandrel 4 be calibrated.

In a further embodiment, the soldering material required for production according to the method can be used simultaneously when deforming the pipe end over the mandrel or simultaneously with the calibration process on the Tube end are molded, namely the latter z. B. by hammering, forging or rolling in a sänne Duplicating.

In a further refinement, the soldering material can

can also be applied to the pipe end as a wrapped film. The soldering foil is therefore mechanical placed, with as a soldering foil z. B. Metglas can be used. The soldering material can, for example also galvanically, by spray coating, by immersion in a soldering liquid or by sintering (solder powder) that or the pipe ends in question are applied.

The relevant gap or the axially parallel cylindrical joint U between the hole wall 5 on the one hand and the relevant pipe end 1 on the other hand is determined by the requirements of the mountability and the manufacturing tolerances. This joint can, however, also be designed as a uniformly tapering conical joint from the outer wall to the inner wall of the heat exchanger.

From Fig. 1 it can also be seen that the pipe end 1 protrudes with a pipe section 8 from the opening below, this axially protruding pipe section 8 by way of the final withdrawal of the tool mandrel 4 from the pipe section with the effect of the federal 6 at least partially laterally over the lower Opening edge is bent (shown in dashed lines).

According to FIG. 1, the basic idea is to pull the tool mandrel 4 together with the collar 6 through the pipe section to be joined or the pipe end 1 in order to suddenly expand the pipe end 1 to close the relevant joint LJ between the hole wall 5 and the adjoining peripheral wall of the pipe end 1 conclude.

In the context of FIG. 1 mentioned and not shown further variant with conical joint, it is assumed that the joint is already closed before the tool mandrel and the collar, which will later be used for flexing, are pulled through the tubular end of the pipe. With the appropriate assignment and dimensioning of the federal government in accordance with the required compression, a solution is thus created which, in relation to FIG. 1 includes a comparatively lower degree of deformation, which in turn leads to a comparatively lower expenditure of force and tool wear as well as correspondingly lower tolerance fluctuations. In the connection method according to FIG. 1, it can be assumed in principle that a counter-bracket is used as an auxiliary device for carrying out the method, which acts to support the heat exchanger base 3 during the manufacturing process against the mandrel pulling movement (arrow direction F) and which is applied from below to the axially protruding pipe section 8 should attack. With this counter-bracket, the bending process of the axially protruding pipe section 8 against the lower edge of the opening and against adjacent inner wall parts of the heat exchanger base 3 can be supported.

Using essentially the same reference numerals for compared to FIG. 1 essentially unchanged components is F i g. 2 a further variant in which the associated opening in the heat exchanger base 3 including the circumferential wall of the relevant pipe end 10, at the same mutual angles of inclination, form a cylindrical circumferential joint U ' which tapers uniformly and slightly conically towards the inner wall of the heat exchanger base 3. In this embodiment, so the concerned

Bund 6 in and of itself no plastic tube deformation, rather this collar 6 is always in the one shown lowest position, in which it is laterally clasped by the axially protruding pipe section 8 '. at the embodiment of Figure 2 is so with the help of Tool mandrel 4 and its collar 6, the conical pipe end 10 into the corresponding conical opening drawn, the relevant circumferential joint [/ 'both with radial as well as axial surface pressure between the associated hole wall 9 of the opening and the pipe end 10 is closed. In the embodiment according to FIG. 2 can also be the tool mandrel 4 can be finally removed from the pipe end 10 by removing the axially protruding pipe section 8 'bent against the inner wall of the heat exchanger base 3 by suitable tools will.

Using essentially the same reference numerals for compared to FIG. 1 and 2 essentially unchanged components Fig.3 differs from j Fig.2 essentially in that the relevant

'Collar 6 of the tool mandrel 4 shortly before the pull-out phase from the pipe end 10 still causes a certain surface pressure of the connection, with it opposite F i g. 2, however, the primary goal of this arrangement of the tool mandrel 4 and the collar 6 - as drawn - is, the lower axially protruding pipe end 8 ″ against the finite extraction process at the same time the inner wall of the heat exchanger bottom 3, which is indicated by the dashed contour of the corresponding Flanged edges should be made clear.

In the relevant embodiments according to FIG. 1 to 3 there / pipe 2 or pipe end 1 or 10 can preferably have a slightly higher coefficient of thermal expansion than the material of the heat exchanger bottom 3 in order to generate additional pressure in the joint U or and i / 'to create.

Notwithstanding the illustrated embodiments, it is entirely possible to use the lower Opening edge axially protruding pipe section before pulling out the tool mandrel against the lower one Bend the opening edge and against the adjacent parts of the inner wall of the heat exchanger or flanging.

According to the profile section according to FIG. 4 are opposite central webs 11 of the tube 2 along whose web ends are welded, two separate channels 13, 14 being provided, which are connected to compressed air can be acted upon as part of the heat exchange process

For this purpose 2 sheets of drawings
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60

65

Claims (14)

Patent claims: 1. Method for connecting the tubes of a heat exchanger matrix to the heat exchanger base (3) a collecting tank, with the correspondingly prepared openings in the heat exchanger base insertable pipe ends (1) are pressed positively to the ground using a tool mandrel (4), which at one end is rotationally symmetrical with the mandrel diameter projecting collar is equipped, characterized in that the respective pipe end (1) Before inserting it into the relevant floor opening, it is coated with a soldering material with which it is - before the onset of heating for the metallurgical connection - within the bottom opening is pressed, the pressing according to an axial pulling movement of the from the beginning in the Pipe end (1) inserted tool mandrel (4) brought about will. 2. The method according to claim 1, characterized in that the respective pipe end (1) before insertion in the heat exchanger base (3), in particular by hammering or forging over the Tool mandrel (4), deformed and after calibration of the outer contour of the same with the soldering material is sheathed. 3. The method according to claim 1 or 2, characterized in that the outer contour of the pipe end (1) is calibrated at the same time when deforming via the tool mandrel (4). 4. The method according to claim 1, 2 and 3, characterized in that as a result of the deformation of the Pipe end (1) via the tool mandrel (4) a rotationally symmetrical pipe widening that corresponds to the collar (6) (7) is formed as a hole stop. 5. The method according to claim 1 or 3, characterized in that the solder material at the same time Deforming the pipe end using the tool mandrel or at the same time as the calibration process of the Pipe end (1) is molded onto the latter, in particular by hammering, forging or rolling in the sense of duplicating. 6. Procedure according to one or more of the claims 1, 2, 3 or 5, characterized in that the soldering material as a wound film on the pipe end is applied. 7. The method according to one or more of claims 1 to 3, characterized in that the Solder material galvanically, by spray coating, dipping in a liquid solder or by sintering (solder powder) is applied to the pipe end. 8. The method according to claim 1 or 4, characterized in that the pipe end (1) so far in the Opening in the heat exchanger base (3) is inserted that a protruding axially over the lower edge of the hole Pipe section (8) when pulling out the tool mandrel (4) with the effect of its collar (6) is bent sideways over the lower edge of the hole, eo 9. The method according to any one of claims 1 to 4 or 8, characterized in that the openings in the heat exchanger base (3) leaving an axially parallel, cylindrical joint ( U) or in the sense of a conical joint that tapers uniformly from the heat exchanger base outer wall to the inner wall. 10. The method according to one or more of claims 1,5,6,7 and 8, characterized in that the openings in the heat exchanger base (3) are prepared so that they are between the hole wall (9) in the heat exchanger base (3) and aer peripheral wall of a pipe end (10) to be inserted, a cylindrical circumferential joint (U ') which tapers uniformly slightly conically from the outer wall in the direction of the inner wall of the heat exchanger base (3) at the same mutual angle of inclination and which is closed under both radial and axial surface pressure when the conical pipe end (10) is pulled into the corresponding conical opening by means of the tool mandrel (4) and its collar (6). 11. The method according to one or more of the claims 1 to 10, characterized in that the respective pipe (2) or pipe end (ί, 10) with a slightly higher coefficient of thermal expansion than the material of the heat exchanger bottom (3) is equipped. 12. The method according to claims 1 to 7, and 9 to 11, characterized in that the over the lower opening edge axially protruding pipe section - before pulling out the tool mandrel - Against the lower edge of the opening and against the adjacent parts of the heat exchanger base inner wall is turned. 13. The method according to claim 1, characterized in that the to be made by heating metallurgical connection of several or all pipe ends with the heat exchanger base is carried out at the same time in one operation. 14. Device for carrying out the method according to claim 1 or 8, characterized by a mandrel pulling movement (arrow direction F) opposite, the heat exchanger base (3) supporting counter bracket, with the additional effect of the axially protruding over the lower opening edge pipe section (8) against the lower Opening edge as well as against adjacent heat exchanger bottom inner wall parts can be bent.